Researchers Warn That Popular Weight Loss Medications May Cause Rare Form of Blindness

( — On Wednesday, July 3, a new study was published in a specialized medical journal for eye health, suggesting a link between popular semaglutide and a rare form of blindness.

Three of the researchers were based out of the Harvard T.H. Chan School of Public Health and Harvard Medical School, and the fourth was from Brigham and Women’s Hospital in Boston. The study’s purpose was to investigate a possible connection between semaglutide, and the rare and still poorly understood condition called NAION.

The onset of NAION is painless and often quite sudden, with patients simply waking one morning with significant loss of vision in one eye. Sight loss comes from the loss of blood flow to the optic nerve, but the ultimate cause of that is still unknown. Some have suggested transient fluctuations in blood pressure may be the problem but that is still a disputed opinion in the medical community. Some believe sleep apnea or certain medications like Viagra may cause NAION but that is also still under debate.

The researchers in this study analyzed data from 6,827 patients from an academic institution who were seen by neuro-ophthalmologists between December 1, 2017, and November 30, 2023. The study showed that patients taking prescription semaglutide dugs were found to be four times more likely to experience NAION. Patients who took the medication who were also overweight or obese had over seven times that probable outcome. Risk seemed higher in the first year after being prescribed semaglutide medications. Of those studied, 17 NAION events occurred in patients who had been prescribed semaglutide, while they only occurred in six who were on other medications for diabetes.

Novo Nordisk, the manufacturer of the only semaglutide medications in the US, has released a statement directly addressing the concerns raised by the new study. They say that patient safety is one of their top priorities, and they take reports about adverse events in connection with their medications very seriously. However, they point out that the data in the new study is not sufficient to establish a causal association in this case. This was a relatively small study with narrow parameters. However, it is recommended that anyone considering the use of semaglutide discuss all possible benefits and risks with their physicians.

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